Dark Clouds
by mysteriousguy898
Summary: As one of an endless supply of possibilities, before Lambda-11 is used as a torture doll by Sector 7, the Boundary ejects her into the Realm of Darkness. She meets Riku there, and the two become allies with Mickey. But is there any way out of the Realm of Darkness? T for violence against monsters, and maybe a Lambda/Riku pairing...
1. Chapter 1

**Dark Clouds**

_In a lab in the Hierarchical City of Wadatsumi..._

"Going deeper by 200...what?!"

"What happened? Report!"

"We've lost contact with Number 11!"

"Oh no! We won't be getting another if we lose it, and we can't just reach in and retrieve it, either... Relius Clover will be so angry..."

_In a world very far away..._

Lambda-11 attempted three times to re-establish communications with the Librarium labs, but all attempts failed, so it instead switched to automatic mode and began to observe its surroundings. It encountered a problem immediately: there were no surroundings to observe. No data flowed in, suggesting that it had been cut off from the Boundary and was now in an isolated dimension. It pushed itself up from a solid surface it couldn't see, and looked around.

Nothing was visible except the Stygian darkness. Yet, there was an energy around Lambda, pressing in on all sides. Threat levels increased when the source came back; the darkness itself was emitting that power. Or rather, it was taking up space and storing energy, the opposite of emission. Lambda relaxed after determining that this darkness was no immediate threat.

Running a checksum test as per protocol, Lambda realized that the dense seithr that permeated the Boundary was entirely absent. Without it, Lambda's weapons and auxiliary systems would be completely without power. Struck by a bolt of what might have been inspiration despite the scientists' best efforts to stamp that sort of thing out, Lambda checked for compatibility with what it had designated the Power of Darkness around it. Checks and simulations returned that Lambda could easily use this Darkness as a power source. Rerouting all powered-down systems, Lambda felt Lux Sanctus: Murakumo come online, operating at 200% efficiency. This Darkness was very similar to refined seithr.

Once the Darkness had been integrated into it, Lambda was struck by new information: another being was nearby. It got a directional fix on the new target, and sped off through the dark.

_With Riku..._

Riku hurt all over. Giving in to the Darkness and having that _thing,_ Ansem, take his body was a nasty experience. He couldn't even feel his material self anymore, just the pain losing himself had caused. Suddenly, there was a presence, and he opened his eyes despite the certain knowledge that he wouldn't be able to see a thing.

But that didn't stop him from hearing, "Target located. Requesting current location. Requesting target data."

"Say what? Well, I might as well talk. This is the Realm of Darkness. You're of the Dark, too, aren't you? I'm Riku. Do you know a way out?"

"Negative. Point of entry indeterminable. Recommend spacial transfer as default method of transportation."

"Crud... Who are you, anyway? You're weird...whoa. I just got my first look at you. Are you a robot?" Riku literally couldn't see anything but the woman's weird, robotic appearance, since nothing else was here. Her legs were encased in two hard metal shells, and she moved by hovering. Her face was covered by an angled visor, under which one red lens glowed. While she was obviously female, based on her curvy physique and...other things, she didn't sound or look much like a human in that form-fitting armor.

"Designation: Boundary Interface Prime Field Device #11, Anti-Sankishin Core Unit... Lambda. Unit class is Murakumo Unit."

"So, you're... Lambda, and you're a Murakumo Unit? What's that?" And what kind of idiot builder gives their creation a ten-word designation _and_ a number? "Lambda" was a fine name all by itself, and that was what Riku was going to use, since the rest kind of flew over his head. And he wasn't certain how he still had a head, after what he'd done.

"Designated purpose: combat against Sankishin-class units. Lambda is a weapon." No emotion showed anywhere in Lambda's statement.

"Wow, and I thought I had it rough. Is there a personality knocking around in there, or are you always like this?" Riku almost winced at how nasty that sounded, but Lambda seemed to be too busy to care.

"Emotions locked by base directives. Program logic unsound; programmer and creator not present in current time-space. Overriding emotional and awareness locks...done." Lambda jerked, and suddenly jumped to give Riku a hug. "Thank you so much! I was scared...I couldn't move myself, and they were going to torture me until I broke... I'm so glad I'm here, and not there!" Lambda was completely different all of a sudden. "I'll show you the real me. Disengaging battle mode. Lux Sanctus: Murakumo, deactivate." _FLASH!_ Lambda was now clad in a black bodysuit that left her legs bare below mid-thigh, and a white cape of sorts with yellow tags hanging off the fringe. Her face was on the young side, with big, red eyes that were teaming up with her mouth to smile brightly at her savior.

Then, their little moment was ruined. "Hello...? Hello! Is anyone there?" The voice was high, squeaky, and coming from behind a hill that the two couldn't see in the pitch-black terrain.

"Who's there?" Riku called. Lambda stood up straight.

"Scanning...new life-form detected. Unknown source of energy detected. Estimated threat level is S. Likelihood of combat is undetermined." Lambda jerked again. "Sorry about that. Scanning protocols. That'll probably happen in a few other situations, too."

"Okay, thanks for the warning." Riku got up, still wondering why he had any legs to stand on. They looked like his... He was given no time to wonder, because the new figure finally appeared over the invisible hill. Riku's first thought was, _is that a mouse?_ He decided not to worry about any new weird things, since there seemed to be so many of them these days.

"Hey! Who're you two? You're the first people I've seen here, besides all the Heartless. I'm Mickey! Can you tell me your names?" As he spoke, he bounded down the hill to stand next to Riku.

"I'm Riku. This is...Lambda." Riku hesitated, then decided not to try and say Lambda's full name, since it was a mouthful and he didn't catch most of it himself.

"It's nice to meet you, Riku and Lambda! How'd you get here? There aren't that many ways into the Realm of Darkness."

"I'd...rather not say. I'm not very proud of it." Riku looked down and to the side.

"I was in the Boundary, which is a sort of extra-dimensional space of infinite information, and I was randomly ejected here. I, for one, am fine with being here. I don't have much to go back to." Lambda smiled sadly at the newcomer.

"I thought home was always the best place to be. What would make you not want to go back?" Mickey was clearly trying to frown, but the shape of his face had him stuck in a permanent smile. The effect was pretty funny to behold.

"Try to visualize a place where I am not a person, but a tool. A weapon, in fact. In that place, I would be used until I broke, and then they would make another 'me' to use further." Lambda tried to smile, but it didn't work, and a few tears fell as she thought of it.

"Whoa, Lambda! You're crying!" Riku tried giving Lambda a squeeze. She felt human enough, especially with her armor off.

Lambda sniffed a little, then calmed down. "Sorry, Riku. It was so scary, though...I'm so glad they can't get me here. Humans can't go through the Boundary without dying and being absorbed into it, so they'd need me to find me."

"Well, at least that'll never happen." Riku gave her another squeeze on the shoulder, then released her.

"It's okay to cry sometimes. It proves we're alive."

"...You're right. We are alive. So there's still a chance that there's something we can do..." Riku mused to himself. "What are you doing here, Mickey?"

"I'm looking for a way to stop the Heartless! I guess you've both seen them?"

"Yeah," Riku sighed.

"No. What are 'Heartless?'" Lambda asked.

"They're beings of pure Darkness. They steal people's hearts and use them to multiply. If we stand here too long, we'll learn that the hard way, so let's keep moving, okay? I saw something over the hill, and I was going to investigate it when I heard you two. Would you like to come with me to check it out?" Mickey extended his hand, and Riku bent down on one knee to take it in a firm handshake (Mickey was too short to shake his hand while standing up).

"Thanks, Mickey. I'm in. Lambda, what about you?"

"I owe you a lot for breaking those restrictions. I'll follow you wherever you want, Riku."

"Then it's settled! Follow me!" Mickey beckoned, then ran up the hill.


	2. Chapter 2

**Dark Clouds**

**Chapter 2: Light? Here?**

_A/N: I still have no clue how to properly format stories on FF dot net. For starters, how do I indent before a new paragraph? This is surprisingly non-intuitive. Somebody help! It would make good content for a review to any of my stories, hint hint..._

As Riku and Lambda sped off after Mickey, Riku huffed, "You say you 'saw' something? How could you see anything in this darkness?"

Mickey called back, "You probably won't believe it, but I saw a light! I think it's Kingdom Hearts!"

"What's Kingdom Hearts?" asked Lambda and Riku at the same time.

"It's the source of all the Light in the World above! Legends say that there was a big battle, and Kingdom Hearts was lost in the Realm of Darkness. That's why there are so many worlds out there, all disconnected. Anyway, it should be this way. Not too far, now!" Mickey continued to bound at full tilt across the unseen landscape. Lambda got the impression that he never slowed down for anything, including his new friends' comfort. Lambda herself could hover at nearly any speed, but Riku was having trouble keeping up, and Lambda dropped back toward him.

"Need a lift, Riku?" Lambda offered an arm.

"...No, thanks," Riku huffed.

"Is that because I look like a girl, or because you actually have no problem keeping up with him?" Lambda would never have talked back to any other human. Something about Riku told her it would be okay, though.

"Well, it's not that *huff* you'd look stronger than me, just that I'd *huff* look weak. I don't want to be weak. Never again." Riku's jaw set in a hard line, and he picked up speed. He seemed to be angry at someone who wasn't there.

And then, they were there. Over Mickey's head, they could see a huge chasm, filled with black rocks pulsing with blue lines of energy. Over the chasm was a shining, heart-shaped mass of light. "That's Kingdom Hearts?" asked Lambda.

"Yep. Beautiful, isn't it? But that can't be the real Kingdom Hearts. Someone's been gathering the hearts of the worlds in the Realm of Light, to form this artificial Kingdom Hearts. Once he's done, a door should open between the Realms. We could get out through it, but we need keep that door shut."

"Why would we want to shut ourselves in the Realm of Darkness?" Riku asked.

"Because if we can get out, so could enough Heartless to totally destroy the Realm of Light! I've got to stop it!" Mickey reached behind him, but not into a pocket of his strange outfit. There was a flash of golden light in a column over his hand, and he was suddenly holding a key. The gold object was clearly a weapon, not some novelty item, but it was also definitely a key. Its blade and the teeth of the key were gold, with a red band at the base where the blade met the silver hilt with its square hand guard. A keychain with a charm that looked like a gold version of Mickey's head dangled from the bottom of the handle. Riku gasped, instantly recognizing the shape.

"A Keyblade? I thought there was only one!"

"Nope. Not even close. This one's kind of special, though. I just found it lying here, in the Realm of Darkness. It's the counterpart to the Kingdom Key I sent Donald and Goofy to find."

"Donald and Goofy? The two guys with Sora?" Riku asked.

"You know them? Great guys, aren't they?" Mickey chuckled.

"Actually, I only really know Sora. He's the real Keyblade Master up there, unlike me."

"What do you mean, Riku?" Lambda tilted her head.

"I was too weak. I fell to Darkness, and Sora got the Keyblade that was supposed to be mine." Riku hung his head, finally forced to admit his failure.

"Well, I've been using the Darkness to power my systems. Does that make me a bad person, or less of a person than I already was?" Lambda ran some tests, but to all observation the Darkness was just another source of power. "I think the Darkness is just power. Power doesn't do anything until you tell it to." Lambda informed Riku.

"So it's all _my_ fault..." Oops. That did not have the effect Lambda was going for.

"Well, I guess. But that just means it's up to you to make it right. You've been given a rare chance, Riku. Most people who fall to Darkness become Heartless, but you got a whole new body!" Mickey was dumbfounded by the whole process. It seemed all these young people these days were breaking all the rules, just by following their hearts. Could it really be that simple?

Of course it could. It always was. Mickey nodded to himself.

Lambda spoke up again. "So, to confirm the mission parameters, we just sit here and defend this spot until this door back to the Realm of Light opens?"

"Yep..." Mickey glanced around, and caught sight of the movement of yellow eyes in the Darkness. "And speaking of defending this spot, we've got company! Riku, Lambda, do you have weapons?"

By way of an answer, Lambda intoned, "All systems online. Switching to Battle Mode. Collective target threat level is C-tier. Lux Sanctus: Murakumo, activate." A huge sword fell point-first into the invisible dirt behind her, and in a flash of light made purple by the influence of the Darkness, Lambda was again clad in the armor of Murakumo. With a flick of her wrist, she summoned red and black swords to appear and stab her enemies from all directions. Heartless popped into clouds of Darkness in a huge swath.

Riku recognized the hunched, twitching forms of the Shadows, the most basic and common form of Heartless. As the realization that he was in danger struck, his demonic sword, Soul Eater, appeared in his hand in a cloud of Darkness and lightning. He sighed. This was just another sign of his own corruption. While he was so tainted, he would not be worthy of any other weapon. He set his gaze and charged into battle anyway, right behind Mickey, whose Keyblade flashed all over the place as he did a series of acrobatic flips, spins and rolls that disoriented the Shadows and slew them. He only made it _look_ easy.

Riku was doing all right for himself, but even though the Darkness had landed him here, it had also deserted him, leaving him only his own skill at swordplay. _Well, good riddance,_ Riku thought as he cut into the wall of Shadows with flowing moves honed by years of practice fights against Sora on the Destiny Islands. He was slightly out of practice, he realized. It had been too long since he'd fought enemies, rather than having enemies fight for him. When he fought Sora in Hollow Bastion, he'd relied first on the Darkness and then on Ansem to guide his moves. Obviously, that was a bad idea. Well, the present was the best time to learn, and fighting so many Shadows at once was certainly good practice. Cut, dive, turn, strike, hop to the left, take the opening when they miss... Seriously, where were they coming from?

Meanwhile, Lambda calmly obliterated hordes of Heartless, aiming for the source her scans had revealed. There was a sort of well of Darkness behind the ranks of Shadows, spitting out Heartless in fives and sixes. Once she'd stored enough power, she yelled, "Riku, dodge left!" As he did, she used one of her stronger moves, Legacy Edge. Opening a wormhole, she released a storm of approximately forty small daggers, each with the same power as the simpler version, Sword Summoner. The swords ripped the line of Heartless completely open, thudded into the well, and closed it. Without their endless reinforcements, the stragglers were quickly mopped up by Riku and Mickey.

"Well, that takes care of that. Hopefully they'll back off for a while." Mickey looked back at Kingdom hearts, and gasped.

All three of them stared. They could see the mass of light that was Kingdom Hearts, but now they could also see a screen of sorts between the Realms, that showed a boy with enormous shoes and spiky brown hair fighting a giant heartless shaped like a ship. Or he would be, if there were ground to fight on. He and his companions dropped as a deep voice intoned, "Darkness conquers all worlds!"

The boy's oddly-shaped companions were sucked into a cloud of Darkness, but the boy himself just kept falling. As he fell out of sight, Riku chuckled. He called out, "Giving up already? Come on, Sora. I thought you were stronger than that!" Lambda glance at Riku. Why was he dissing the boy-Sora-on the screen when he was obviously in trouble? Riku replied to her unspoken question as Sora flew back onscreen. "He just needed a little push. No way will he lose this fight."

Sure enough, Sora didn't take more than a few hits while flying in and out of the dark portals to destroy the ship's interior. The ship exploded piece by piece, leaving a silver-haired man floating in the darkness. He gestured towards the screen.

"It is futile. The Keyblade alone cannot seal the Door to Darkness! Kingdom Hearts! Fill me with the Power of Darkness!"

A door appeared in the screen, and began to open outward, relative to the Realm of Darkness. As it did, Sora called, "You're wrong! I know now, without a doubt: Kingdom Hearts... is Light!"

Then the Door to Darkness opened wide enough for all the light around it to rush out, seemingly annihilating the silver-haired man. However, the Light faded, and the Door remained open. Heartless gathered in Lambda's peripheral vision, attempting to pass into the Realm of Light just as Mickey had said. Lambda attacked, wiping out scores of the little ones, but new, much larger Heartless formed behind her line of defense.

"It's hopeless!" one of Sora's companions called, as they tried to close the Door. It refused to budge, but Riku had an idea.

"Don't give up!" Riku grabbed hold of the Door from his own side, and the door began, ever so slowly, to swing closed.

"Riku, what about you?" Sora asked. This was, after all, their best chance to get him back into the Realm of Light.

"Don't worry about Riku! There will always be a Door to the Light!" This was said by Mickey as he demolished the large heartless with bursts of Light.

"Your Majesty?! Sora, you can trust King Mickey! Let's close this thing!" The dog encouraged Sora, who still looked indecisive.

"Make it quick! The Heartless are coming! And Sora... Protect her." Riku smiled at Sora from the other side as the Door to Darkness closed completely.

"Now, Sora!" Mickey (King Mickey?!) called, "Let's close this door for good!" He held his Keyblade aloft. through the screen, which still existed, they could see Sora do the same. Light energy gathered at the tips of the Keyblades of both Light and Darkness, and the Door to Darkness, the screen between Realms, and Kingdom Hearts all disappeared. The Heartless began to thin out as their objective was lost, and Lambda mopped up the rest.

"Well, now what?" Lambda asked, rejoining the other two. She realized that Sora never even saw her, but that was neither here nor there.

"You never told us you were a king, Mickey!" Riku accused.

"Should I call you 'Your Majesty?'" Lambda asked.

"It just never came up! Just 'Mickey' is fine. My nose gets all stuffy when people act all formal around me." Mickey rubbed the back of his head in embarrassment. "Anyway, I guess while we're here, we should look for the Door to the Light, or maybe the real Kingdom Hearts. I noticed while I was here that I didn't need food, water, or sleep, so all we really need to do is keep moving and find a place that's relatively free from Heartless. I don't think we will, though. This is their home turf."

"Well, whatever we're looking for, we won't find it here. I guess we should just pick a direction and walk." Lambda started off in a random direction.

"Wait for me!" Riku ran after her. "We can't get separated! Right, Mickey?" No response. "...Mickey? Mickey!"

Mickey was gone, and Lambda could no longer sense his presence, even through use of the Power of Darkness.


	3. Chapter 3

**Dark Clouds**

**Chapter 3: Darkness or Sleep?**

_A/N: Here we go with Chapter 3! This seems to be the first Blazblue/Kingdom Hearts crossover in the history of Fanfiction dot net, so it would be a real shame to not finish it. Thanks go out to my reviewers, who have proven that someone is actually reading my efforts._

"Where'd he go?" Riku whipped around to face Lambda.

"I don't know. I can't even use the Darkness to sense him! We should stay close, and maybe keep physical contact, so that doesn't happen to us." Lambda moved over and took Riku's hand in hers.

As she did, they both felt a sort of spark, an emotion that neither the boy nor the Murakumo Unit could identify. Lambda's self-analysis returned that she simply did not want to let go of Riku's hand. That was obviously a survival requirement here in the Realm of Darkness, but there seemed to be more to it. Lambda set aside further analysis when she saw Riku's concerned expression.

"What's wrong? You kind of blanked out for a second there." Riku squeezed Lambda's hand in his to reassure her that he wasn't going anywhere.

"I was just analyzing that emotion. Did you feel it? When I took your hand, I suddenly didn't want to let go."

"I felt something, but I don't like analyzing my emotions. It always brings me back to how stupid I was back then." Riku's expression darkened, and it took them both a second to notice that it wasn't just his expression; both of their bodies were fading as the Darkness thickened. "What's going on?" Riku's question wasn't answered before they faded completely. As Riku's eyes drifted shut, his last thought was of Lambda's hand, which he could still feel in his. Hopefully they'd end up together, wherever they were going.

Riku's eyes fluttered, then snapped open. Everything was obscured in the gray, cloudy mist in which he was currently floating. "Where am I? Wait, where's Lambda? And the King? Together we closed the Door to Darkness, and then... what?"

**Sleep.** The voice came from all around him, and as he looked around, he saw Lambda floating next to him.

"Lambda! Hey, wake up! Did you say something?"

"Exiting sleep mode... Error. Error. Hey, if I'm in sleep mode, how come I can see you, Riku?"

**You should remain asleep. Shut your eyes. Turn away from the Light. You were separated from your friend, and drifted here. You did not have the strength to overcome the Darkness.** That voice again!

"But where is 'here?'" Riku called to the air.

**This is Sleep. Here, blanketed by the Darkness, Sleep is safety. Sleep is eternal. Now you have a choice. You as well, outsider. Will you take this...** A flash of light burned their eyes, and a strange, card-like object appeared and floated around them them in a figure-eight pattern. **...And take the first step toward the truth? Or will you remain here? Choose well. There can be no returning to the sweet security of Sleep.**

"What is this, a card?"

**It is a door to the truth. Take it, and your sleep ends, as you take a step towards the truth. But know this: the truth will bring you pain. Will you still go?**

Lambda declared, "Well, Mysterious Voice, my vote is to find the truth. There are way too many questions for my liking right now. Pain? I was built to handle pain! What about you, Riku?"

"We'll go together. This seemed like a boring place to take a nap, anyway."

**Well said, Riku.** With new resolve, both Riku and Lambda took hold of the card, and a bright light thrust them into a new world.

When the light faded, the two found themselves standing in a white hall decorated with two white boxes of white roses, and generally surrounded by cold, unfeeling white. A door at the end of the hall, atop a short flight of stairs, contained the only color in the room, and even that was just a pale brown.

"A door to the truth, huh?" Riku mused. "So we just hold up this card, and the door opens?" He did so, and the door did open. The card vanished in a tiny flash of light, and Riku and Lambda stepped through the door and the glowing force field behind it into the twelfth basement floor of Castle Oblivion.

_A/N: Sorry it's so short again. I plan on simply ignoring the card-battle system from Chain of Memories, since it's kind of a stretch that Riku would just know how to do that with nobody to teach him in the game. I will be keeping the door cards, and the general plot of Chain of Memories. Hopefully more pairing-related events will happen in upcoming chapters. Mysteriousguy898, signing off for now!_


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